The subject matter of the present invention is casting resins on the basis of hardenable acrylic and methacrylic acid esters and finely divided, inorganic fillers, which contain polymeric organosilicon compounds as adhesivizers.
It is known to mix inorganic fillers with casting resins on the basis of hardenable acrylic and methacrylic acid esters, which will be referred to hereinafter also as unsaturated casting resins. Furthermore, casting resins containing the inorganic fillers in amounts exceeding 50% are known, in which these fillers are to be especially finely divided. In these last-named casting resins the use of monomeric organosilanes as adhesivizers has already been described (cf. German Fed. Pat. No. 24 49 656). These known casting resins containing finely divided fillers have higher densities, greater hardness and improved stiffness in comparison with unfilled unsaturated casting resins.
Furthermore, the inorganic fillers reduce the heating of the resins while they are setting, as well as their shrinkage.
The high content of finely divided fillers, which, when used with monomeric organosilanes as adhesivizers, are uniformly distributed in these casting resins, increases the flexural strength and impact toughness of the moldings made from these resins. The moldings which are made from these known unsaturated casting resins include sanitary articles such as sinks and lavabos.
In the production of these moldings, the unsaturated casting resin is to have the lowest possible viscosity so that, when the molds are filled, they will be completely filled out, and the necessary degree of filling can be maintained. On account of the high content of fillers, this requirement is not met by a great number of unsaturated casting resins. This problem cannot be solved even by the addition of monomeric organic silicon compounds; some organic silicon compounds even work to produce a further increase of the viscosity.
It is already known from German Federal publication No. OS 33 31 371 that monomeric and polymeric organosilicon compounds, when mixed with metallic acid esters of metals of Group IV or V of the periodic system of the elements produce a reduction of the viscosity of the compositions according to German Federal Patent No. 24 49 656. At the same time this system also results in an improvement of the mechanical properties.
The problem existed of further improving the adhesivizer system of organosilicon compounds and metallic acid esters specified in German publication No. OS 33 31 371 by striving for an additional great reduction of viscosity. The casting resins thus obtained were to simultaneously retain the known good physical characteristics of the casting resins in the state of the art, and even improve upon them if possible.